The invention relates to an open motor vehicle such as a convertible, roadster or the like with an air vent opening to a seat headrest area for supplying fresh heated air.
In a known motor vehicle of this type (German Patent Document DE 197 00 739 C1), the fresh-air/heating device is of flat design and is integrated into a windbreak which is arranged behind the backrests of the vehicle seats and covers the headrest region. The heating device heats the cold air which flows through the windbreak owing to the reversal of the relative wind and reduces in this way troublesome air draft phenomena when driving without a top and thus also makes it possible to drive with the top down at low external temperatures. The heating device is arranged in the form of an electric heating wire mesh within the windbreak frame or is adjoined parallel to the windbreak as an inherently rigid structure and is connected to said windbreak by means of attachment elements. As an alternative, the heating device can also take the form of a plate or disc heat transferring device, in which case it can be operated with liquid or gaseous heat transfer media in a heat transfer circuit.
When the fresh air/heating device is embodied in such a way, shoulders, neck and throat of the vehicle occupant which are particularly sensitive can be pleasantly air-conditioned. However, a draft of cold air flows into the rear part of the vehicle via the opening which exists between the windbreak and the rear wall of the vehicle interior in some motor vehicles, and gives rise to considerable draft phenomena in the region of the legs. The heating device is also relatively complex.
In another known motor vehicle (German Patent Document DE 92 01 474 U1), in order to reduce the air draft phenomena which are troublesome to the vehicle occupants, air streams which emerge from an air vent which is arranged in the headrest region of the vehicle seats and directed obliquely upwards and to the rear are fed in a targeted fashion to the shoulder and neck region of the vehicle occupants when driving with the top down. In order to generate these air streams, air is collected from inlet openings provided on the vehicle and fed to the air vent by means of ram pressure and/or a blower.
In a motor vehicle with an internal combustion engine it is known to heat the vehicle interior by means of air heated by the exhaust gases (German Patent Document DE PS 850 998), the heat-transferring components which are arranged in a safety space which is positioned between a fresh air heater which is fed with fresh air and the exhaust line are designed, for the purpose of improving the heating performance, as metallic intermediate elements which connect the wall of the exhaust line to the inner wall of the fresh air heater. The inner wall of the fresh air heater is provided with indirect heating faces which extend into the fresh air heater.
The invention is based on an object of improving the air conditioning when driving with the top down in an open motor vehicle of the type mentioned at the beginning, and of thus improving the sense of well-being of the vehicle occupants.
The object is achieved in an open motor vehicle of the type mentioned at the beginning in accordance with the invention by providing an arrangement of the above described type, wherein the at least one air vent is arranged underneath the sill line of the vehicle body and is arranged on or in the rear wall of the vehicle interior.
The motor vehicle according to the invention has the advantage that the waste heat of the drive device, in particular for example of the internal combustion engine and/or of the gearbox and/or of the exhaust system, is used to heat the air, and the air which is heated in this way is mixed with the cold air flowing into the rear region of the vehicle, and as a result no unpleasant cold air streams can be felt anymore either there or in the footwell of the rear part of the passenger compartment. As a result of the fact that the warm air leaving the air vent flows out in the direction of the upper side of the backrest or the lower region of the headrest, warm air is applied directly and more intensively to the shoulder and neck region of the vehicle occupants, which improves the sense of well-being of the vehicle occupants while driving with the top down. The fresh-air/heating device is, in contrast with the known motor vehicle, part of the vehicle itself, for example part of the vehicle body, and is not arranged specifically in the windbreak. As a result, the design of the windbreak does not have to fulfil structural requirements which arise from technical considerations. The forced ventilation of the air duct can either be effected by means of ram pressure which occurs during driving or by means of a gearbox. The utilization of the waste heat of the drive device with internal combustion engine, gearbox and exhaust system which remains unused in conventional vehicles is exploited in the invention to heat the air, and dispenses with the need for additional energy sources for heating, when required.
Advantageous embodiments of the motor vehicle according to the invention with expedient refinements are described herein and in the claims.
In one advantageous embodiment of the invention, the at least one air vent is arranged under the sill line of the vehicle body on or in the rear wall of the vehicle interior, in which case it can preferably extend over the entire width of the vehicle interior. In conjunction with a windbreak which is assigned to the vehicle seats and which is arranged behind the backrest so as to cover at least the headrest region and is positioned in front of the air vent, a significantly improved level of airconditioning comfort is obtained when driving with the top down.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.